The present invention relates to an image display apparatus including an input unit such as a keyboard, a computer body and a display unit, and more particularly to an image display apparatus in which a display size, a display position and brightness of a picture in the display unit can be adjusted by the input unit such as the keyboard through the computer body to improve the handling capability. The image display apparatus of the present invention can be used in a work station and an advanced personal computer using a display unit.
At present, in the display units for a computer terminal, the display position and size of the picture and a deflection frequency of a video signal to be displayed are variously different. Accordingly, one display unit for the computer terminal is designed to be able to treat various video signals.
The display unit of this type employs a microcomputer and an LSI memory to provide an optimum picture display for each kind of video signals. Such a display unit in a prior art is disclosed in Japanese Patent Unexamined Publication No. 1-321475, for example.
This conventional display unit is directed to a multi-scan type CRT display unit, which includes a memory in which information relative to display positions and sizes of the picture is stored for each kind of video signals and which is controlled by a microcomputer in that display unit. The information relative to the optimum display position and size of the picture in accordance with an input video signal is read out from the memory and a deflection circuit of the display unit is controlled by the read-out information. Further, when a video signal inputted in the display unit is not known, the memory stores no information relative to the inputted video signal and accordingly adjustment switches disposed on a front panel of the display unit are operated without the intervention of the computer so that information for adjusting the display position and the display size of the picture is inputted. A control circuit such as the microcomputer prepares information for control including deflection and makes adjustment.
In the prior art described above, the display unit is designed to obtain the optimum picture display in accordance with the input video signal, while, in another prior art, a display state is controlled to be switched from the computer body in accordance with the variety of the multi-media. Such a display unit in the prior art is disclosed in Japanese Patent Unexamined Publication No. 2-60193.
This conventional display unit is directed to a CRT display apparatus used in display of an electronic apparatus such as a personal computer and which can switch the number of scanning lines between 200 lines and 400 lines freely and be shared by a television receiver.
More particularly, in the above prior art, the computer body produces a discrimination signal superposed on an video signal during a blanking period and the display unit switches the deflection frequency on the basis of the discrimination signal.
In the former prior art (Publication No. 1-321475) of the above two prior arts, since the display position and size of the picture are all controlled by the display unit, it is necessary for the operator to separate his fingers from the input unit such as the keyboard connected to the computer body and extend his hands to the adjustment switches of the display unit disposed at a separate location to operate the switches when the adjustment of the display position and size of the picture are required. Accordingly, it is troublesome in the handling capability.
Further, in the latter prior art (Publication No. 2-60193), the display state is controlled by the input unit such as the keyboard connected to the computer body, while since only the deflection frequency can be switched only by a binary value, there is a problem that only two specific signals can be treated and a sufficient display state required by the user of the computer can not be obtained.